Apparatus for measuring air-currents.



No. s9|,0s2. Patented Jan. 14,1902. .1. THOMPSON.

APPARATUS FOR MEASURING AIR CURRENTS.

(Application filed Jan. 5, 1901.) (No Model.) 2 Sheets-Sheet I,

d dd

1111111111 IIIIIIIU WITNESSES. INVENTOR No; 69l,082. Patented Jan. 14,I902.

J. THOMPSON. APPARATUS FOR MEASURING AIR CURRENTS. 1 (Applicationfileduanfs. 1901.!

(No Model.) I 2 Sheets'Sheet 2.

WITNESSES.

T at whom, it nuty concern:

UNITED STATES- I JOSEPH THOMPSON, OF MANCHESTER, ENGLAND.

APPARATUS FOR MEASURING AlR-CURRENTS.

, SPECIFICATION forming part of Letters Pa tent No. 691,082, datedJanuary 14, 1902.

Application filed January 5, 1901. Se'rialNo. 42,261. (No model.)

Be it known that I, J OSEPH THOMPSON, a subject of the Queen of GreatBritain, and a resident of Manchester, in the county of Lancaster,England, have invented certain new and useful Improvements in Apparatusfor Ascrtaining the Velocity of Air-Currents, of which the following isa specification.

This invention is designed to provide apparatus for determining andascertaining with scientific accuracy the volume of ventilation(indicated in cubic feet per minute) passing through coal-mines or otherunderground workings or structures. The apparatus or instrument may beplaced in the ventilating-current of a coal-mine or other situation atany point or points where it is desired to ascertain the amount orvelocity of air passing, such velocity providingthe essential data fromwhich the volume can be calculated at any distinct points or stations.Hitherto the accuracy of such instruments, particularly in coal-mines,has been elfected by the deleterious matter carried by the atmosphere inwhich they have been placed, such as noxious gases,--moisture, steam,vapor, smoke, greasy matter, oil, exhalations from a number of men andhorses below ground, gases exuding from the pores of newly-cut coal, andthe like. My invention excludes all such deleterious matter from theworking parts of the apparatus,and while employing electricity isperfectly proof against electric sparking and is perfectly safe to usein an explosive atmosphere. It will be fully described with reference tothe accompanying drawings.

Figure 1 is a vertical section of the instrument. Fig. 2 is a sectionalplan. Fig. 3 is a perspective View with part of the casing broken away.

The instrument is constructed with a vertical rotating spindle a, to theupper end of which is attached by horizontal arms I), radiallytherefrom, in the form of a cross, four hemispherical cups 0. The cups 0are adjustable onthe same arms by nuts d, traversing a screw-thread outupon the extremity of the arms. The arms are also marked with a scale tofacilitate the accurate adjustment and setting of the cups 0 thereon.

The foot of the vertical rotating spindle a rests upon a cone-bearing e,secured to the base-platef of a'chamber g, in which it is inclosed. Thebearing 6 is formed of a projecting pin or stud and is surrounded by acup h to protectit. The chamber 9, in which the spindle rotates, isfilled with a non-conducting liquid, such as petroleum-oil, which willbearing is rendered air, dust, and vapor proof I by an oil-cup it, intowhich depends a flange 0, projecting from the underside of the radialarms I). The flange 0 rotates in the oil-cup n, and the outer flangepcovers the outer edge of the oil-cup and rotates free of it. Thebearingm projects down into the oil in the chamber 9 and is thus sealedand rendered dust-proof also'at the lower end.

The radial arms I), carrying the cups 0, are

securely attached to the vertical spindle a by a screw-knob r orotherwise.

. On the spindle a is affixed a cam or eccentric s, which rotates withthe spindle, and inside the chamber 9 is placed a contact-piece t,supported by and insulated from the easing f by an insulating-piece '0,all of which are submerged in the non-conducting oil or liquid in thechamber 9. The contact-piece t is connected by a wire w with a terminalw outside the case it, and the spindle is in electrical contact with thecasing f, which is connected by a wire with the terminal y. As thespindle a rotates the eccentric s alternately makes and breaks contactwith the contact-piece t, and the rapidity of such making and breakingof contact transmitted over an electric wireis indicated at anyconvenient station or stations or receiving instrument. An oil-inlet.with protectingcover is shown at w. Rotary motion is imparted tothe cups 0 as they are caused to revolve with the vertical spindle a, bythe current of air passing over them. The ratio of velocity at which thecups move to that of the current of air passing over them is well known,obviously, therefore, by the use of a bell or other form of sounderplaced at the outer or receiving end of the electric circuit. Thevelocity of the current at the site of my transmitting apparatus isascertained by a very simple process.

What I claim as my invention, and desire to protect by Letters Patent,is

1. In apparatus for indicating the volume or speed of aventilating-current of air, the combination with a rotating verticalspindle, air-cups by which it is rotated, and a conicalfootstep-bearing, of an inner chamber 9 filled with a non-conductingliquid in which the spindle is submerged, a cover 70 inclosing the innerchamber, a cam on said spindle rotating therewith and an insulatedcontact-maker in the closed chamber with which the cam makes and breakscontact at each revolution and means for preventing the entrance of dustto said chamber substantially as described.

2. In apparatus for indicating the volume or speed of a current of air,the combination with a rotating vertical spindle, air-cups by 25 whichit is rotated and a footstep-bearing, of a closed chamber filled with anon-conducting liquid in which the spindle rotates, an upper bearingprovided with an oil-cup, and a flange depending from the rotating armsof 0 JOSEPH THOMPSON.

\Vitnesses:

I. OWDEN OBRIEN, FRANK SPARKES.

